Electronic devices with user interfaces in the form of touch sensitive surfaces, such as touchpads and touch-sensitive displays (also referred to as “touch screens” or “touchscreens”), are well known in the art. Touch-sensitive surfaces may serve as a user-interface by detecting a user input object (such as a stylus, a user finger, or a user hand) that touches an active area of the surface. Thereby, the touch-sensitive surface not only detects that an object touches its active area; rather, it also detects where the object makes contact with the active area, i.e., the touch-sensitive display may extract positions (such as x- and y-coordinates) of the contact area (for example, the geometric mean position or, if the active area is divided into segments, all segments that are contacted) between the touch-sensitive surface and said user input object. A wide variety of different sensor technologies may form the basis of touch-sensitive surfaces. Accordingly, touch-sensitive surfaces may be based on resistive, capacitive (e.g., surface capacitive projected capacitive, mutual capacitive, or self capacitive), surface acoustic wave, infrared, optical imaging, dispersive signal, and acoustic pulse recognition sensor technology. Depending on their sensor technology, some touch-sensitive surfaces are suitable for detecting only a single contact, and other touch-sensitive surfaces are suitable for detecting multiple contacts.
Touch-sensitive surfaces in the form of a touch-sensitive display fulfill an additional function: they display information generated by their respective electronic devices.
When an area of the touch-sensitive surface is touched, the touch-sensitive surface extracts positional information from the touch event, submits the extracted positional information to controller means of the electronic device. Depending on the current state of the electronic device, the electronic device may remain in the current state or is transitioned into another state. This functionality allows the user of such an electronic device with a touch-sensitive surface to exert control over functions of the electronic device. Considering a telephone as an example electronic device, the user may unlock the telephone, place a call, or call up an address book. Considering a personal computer (or tablet computer) as another example electronic device, the user may place commands regarding a graphical user interface, change the perspective of a displayed object (such as a map), etc.
Touch-sensitive surfaces primarily generate a two-dimensional data representing the mean position of a physical contact between user input object and the touch sensitive surface. Accordingly, touch-sensitive surfaces acting as user interfaces allow for user input with only two degrees of freedom.
However, many applications running on electronic devices require three- or multi-dimensional control possibilities extending beyond conventional two-dimensional control (i.e., two degrees of freedom) provided by regular user interfaces, such as touch-sensitive surfaces, computer mice, and track balls. Examples thereof are applications that display three-dimensional content, such as: Google Earth (and similar systems for providing geographic information); 3D rendering software for 3D construction and 3D visualization (e.g., AutoCAD 3D, Photoshop, cinema 4D); user interfaces displayed in three dimensions by 3D televisions and 3D mobile phones; and 3D games. For providing control in 3D environments, it is self-evident that more than two degrees of freedom are desirable.
In the prior art, it is known to provide user interfaces with additional degrees of freedom, extending beyond conventional two-dimensional control, by providing additional control elements. Examples for such additional control elements are computer mouse scroll wheels as well as look and move joysticks. These control elements, nonetheless, impose a series of problems: First, they are typically not based on or agree with the user's intuition and are thus not readily learned or understood. Further, according additional control elements are typically bulky and impractical to carry along with, especially in view of state of the art mobile devices (e.g., tablet computers and mobile phones) that typically comprise little more than a touch-sensitive surface and/or display as its primary user interface. Additional control elements do not integrate seamlessly with such touch-sensitive surfaces. On the contrary, the user perceives them as differing from touch-sensitive surfaces in nature and character to the point of incompatibility. Finally, these additional control elements have in common that they are subject to significant mechanical wear.
Accordingly, there is a need for more intuitive, user-friendly multi-dimensional control possibilities that integrate seamlessly with electronic devices (in particular small-scale, mobile electronic devices) with touch-sensitive surfaces, such as mobile phones and tablet computers, and that experience no mechanical wear.
The present invention has been devised and embodied to overcome at least some of the abovementioned shortcomings and to obtain further advantages.